Chlorination of titanium bearing materials



June10, 1941. l P CHUKAS 2,245,358'

CHLORINATIO OF TITANIUM BEARING MATERIALS Filed July 14, 1939 i \IAPORS FROM FURNACE 170w F8613 Tlclq SPRAY 6 CONDENSER .INVENTOR. ALPHONSE PECHUKAS BY @MXW ATTORNEY.

Patented June 10, 1941 CHLORINATION OF TITANIUM BEARING MATERIALS Alphonse Pechukas, Barberton, Ohio, assignor to Pittsburgh Plate Glass Company, Allegheny County, Pa., a corporation of Pennsylvania Application July 14, 1939, Serial No. 284,561

Claims.

This invention relates to a method of chlorinating titanium bearing materials containing a substantial quantity of iron, generally in excess of 10 percent, and is particularly adapted to the chlorination of ores such as ilmenite. In the chlorination of such ores it is known toconduct the treatment in the presence of suflicient reducing agent and at temperature sumciently high to form and volatilize a mixture of iron and titanium chlorides. However, this process has never achieved success due to the iactthat the apparatus rapidly becomes plugged with condensed iron chloride. Attempts to fractionally condense the iron chloride and thus to separate the iron from the titanium tetrachloride vapor have not been satisfactory due to the fact that it is practically impossible to achieve an accurate separation of the iron chloride by ordinary methods.

In accordance with my invention,.I have discovered a method of avoiding plugging of the condenser system. I have found that if the mixed vapors of iron and titanium chlorides are cooled to condense iron chloride, the cooled vapor mixture contains a large amount of iron chloride suspended therein :in the form of vein? fine particles. This iron chloride collects in the various conduits within the condenser system thus plugging the apparatus. I have also found that by washing the gaseous mixture containing solid iron chloride and more or less uncondensed titanium tetrachloride with liquid titanium tetrachloride, substantially complete removal of iron chloride from the vapor may be secured. This washing may be conducted during cooling of the vapors whereby a portion of the titanium tetrachloride is condensed. or subsequent to such cooling.

The vapor mixture may be produced by any convenient method. I have found it desirable to utilize the process described in a copending ap'-- plication of Irving E. Muskat, Serial No. 282,198, filed June 30, 1939. In accordance with this process ilmenite ore or other titanium-iron bearing material is mixed with to 35 percent of carbon and is chlorinated at a temperature above 600 0., preferably at 850 to 1250" C. Other chlorination methods may be used if desired.

The vapors containing iron chloride and titanium tetrachloride may be cooled to a convenient temperature below the temperature at which ferric chloride vaporizes. In the event that it is desired to avoid condensation of titanium tetrachloride with the iron chloride the vapor temperature should be heldabove the dew point oi! titanium tetrachloride, for example, above 75 C. However, in many cases it is found advantageous to condense a quantity, generally not less than about to percent, of the titanium tetrachloride with the iron chloride and in such a case the vapor temperature will be maintained at or below the vaporization point of titanium tetrachloride.

I have found that when a mixture of iron and titanium chlorides is cooled a large portion or substantially all of the iron chloride solidifies. However, much of the solidified iron chloride remains suspended in the vapor mixture and as a consequence is carried over into other parts of the condenser system. By washing the gaseous mixture with liquid titanium tetrachloride, however, the major portion of the suspended iron chloride is removed and the residual vapor may be conducted to another'portion oi the condenser and cooled to condense titanium tetrachloride without fear of plugging the apparatus. The washing may be eflected by spraying the gases with titanium tetrachloride.

The iron chloride thus precipitated is collected with a substantial quantity of condensed liquid titanium tetrachloride. The tetrachloride may be distllledofl? by heating at a temperature above the boiling-point thereof and below the vaporization point of the iron chloride, and may be recovered by suitable means. The uncondensed vapors which remain after condensation and removal of the iron chloride may be cooled to condense titanium tetrachloride vapor thus.

permitting the production of the tetrachloride .in a relatively high state OLpurity.

In accordance with one modification of my invention the titanium tetrachloride which is collected and/or condensed with the iron chloride may be separated from the iron chloride by disiron chloride.

The accompanying drawing diagrammatically illustrates a convenient apparatus for conducting the process in accordance with my invention. In accordance with the modification herein illustrated, vaporized iron and titanium chlorides are discharged from the chlorination furnace into ferric chloride condenser I where iron chloride and a substantial quantity of titanium tetrachloride are condensed by reduction of the temperature to a suitably low value for example, 75 C., or below. The condensed mixture settles to the sloping floor 3, where it is transported by scrapers or other conveying means (not shown) into jacketed chamber 5. During passage of the condensed chlorides through chamber 5, they are contacted with the uncondensed vapors leaving condenser I, whereby all or a major portion of the titanium tetrachloride is revaporized. Eventually, the ferric chloride is discharged into chute l, and is conveyed to a ferric chloride bin (not shown).

The vapors containing the titanium tetrachloride and a quantity of unprecipitated ferric chloride which is generally in the form of fine solid particles are then conveyed to -a suitable condenser or chamber 6, which is provided with a sprayhead ill, to which liquid titanium tetrachloride is supplied through conduit 1. The incoming vapors are thus bathed with liquid titanium tetrachloride whereby a portion of the titanium tetrachloride therein may be condensed and the residual iron chloride is separated from the vapors. The liquid titanium tetrachloride containing the iron chloride is removed through outlet l0, filtered and a portion thereof returned or other. materials which contain in excess of 20.

percent of titanium.

While titanium tetrachloride is found to be particularly eflective as a means of removing suspended iron chloride from vapor mixtures, other liquid metallic halides such as silicon or stannic tetrachloride or titanium tetrabromide or titanium tetrafluoride also may be used for this purpose. Similarly, certain organic halides such, as carbon tetrachloride are found to be cfto the sprayhead. Uncondensed gases are withdrawn through conduit 9 and subjected to further condensing operations for recovery of the remainder of the titanium tetrachloride in a very pure state.

The following example is illustrative:

Using a furnace having an internal diameter of 15 inches which was preheated to a temperature of 1000 C., briquettes prepared from a mixture containing 100 parts ore, 23 parts C and 14 parts molasses, were introduced at a rate of 120 pounds per hour and chlorine at 2.0 to 2.5 pounds per minute. The temperature was maintained at 850-1000 C. throughout the experiment. The vapors were withdrawn from the furnace and cooled to 40 C. whereupon 90 percent of the ferric chloride and a portion of the titanium tetrachloride were simultaneously condensed.-

The gaseous mixture containing condensed iron chlorides suspended therein was passed through a spray of liquid titanium tetrachloride until all of the solid iron chloride was precipitated. The washed uncondensed vapor was withdrawn and cooled to 0 C. to recover titanium tetrachloride. The process was carried on continuously for many hours by introducing briquettes at a rate of 210 pounds per hour, chlorine at a rate of 2.0 to 2.5 pounds-per minute. The condensed and precipitated iron chloride containing liquid titanium tetrachloride was transferred to another portion of the condenser system and was heated to 140 C. in a stream of the washed uncondensed gas, which was obtained after removal of the iron chloride, until all of the titanium tetrachloride was vaporized. The titanium tetrachloride in the vapors was then recovered by cooling to 0 C. No plugging occurred during the entire operation. In addition the step of washing the vapors resulted in a more complete condensation of ferric chloride. Thus the liquid titanium tetrachloride used not only precipitated the condensed and suspended iron chloride, but also produced a more eflicient condensation of the iron chloride vapors.

feotive where the halide is suificiently stable and is liquid at the temperature of operation.

Although the present invention has been described with reference to specific details of certain embodiments thereof, it is not intended that such details shall be regarded as limitations upon the scope of the invention except insofar as included in the accompanying claims.

I claim:

1. A method of removing iron chloride from a vaporized mixture of iron chloride and titanium tetrachloride which comprises condensing iron chloride in the mixture and washing the vapor mixture containing at least a portion of the iron chloride with liquid titanium tetrachloride to precipitate suspended solid iron chloride.

2. A method of conducting the chlorination of an iron titanium bearing material while minimizing plugging within the system which comprises chlorinating the material at a temperature above the vaporization point of iron chloride and titanium tetrachloride to produce a vapor mixture of 'said chlorides, cooling the mixture to condense iron chloride and washing the vapor mixture containing at least a portion of the iron chloride with liquid titanium tetrachloride to remove suspended iron chloride.

3. A method of removing iron chloride from a vaporized mixture of iron chloride and titanium tetrachloride which comprises condensing iron chloride in the mixture, washing the vapor mixture containing at least a portion of the condensed iron chloride with liquid titanium tetra chloride to precipitate suspended solid iron chloride and subsequently separating condensed titanium tetrachloride from the condensed and precipitated iron chloride by distilling the same in the presence of the washed uncondensed vapors.

4. A method of removing iron chloride from a vaporized mixture of iron chloride and titanium halide which comprises condensing iron chloride in the mixture and washing the vapor mixture containing at least a portion of the iron chloride with liquid titanium tetrahalide to precipitate suspended solid iron chloride.

5. A method of removing iron chloride from a vaporized mixture of iron chloride and titanium tetrachloride which comprises condensing iron chloride in the mixture and washing the vapor mixture containing at least a portion of the iron chloride with liquid metallic halide to precipitate suspended solid iron chloride.

6. A method ofremoving iron chloride from a vaporized mixture of iron chloride and titanium tetrachloride which comprises condensing iron chloride in the mixture and washing the vapor vaporized mixture of iron chloride and titanium mixture containing at least a portion of the iron chloride with liquid metallic halide of the group consisting of silicon tetrachloride, stannic chloride, and titanium tetrachloride.

7. A method of removing iron chloride from a vaporized mixture of iron chloride and titanium tetrachloride which comprises condensing iron chloride in the mixture and washing the vapor mixture containing at least a portion of the iron chloride with liquid halide to precipitate suspended solid iron chloride.

8. A method of removing suspended solid iron chloride from a vaporized titanium tetrachloride which comprises washing the vapor with liquid titanium tetrachloride to remove the suspended solid iron chloride and removing the washed vaporized titanium tetrachloride.

9. A method of removing iron chloride from a.

tetrachloride which comprises condensing iron chloride in the mixture together with a portion of the tetrachloride and washing the vapor mixwashed titanium halide vapor.

ALPHQNSE PECHUKAS. 

